2600 Magazine

2600 Magazine - Volume 1, Number 3

ZOUU March, 1984

— — — ==

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FSLN 3 VOLUME ONE NUMBER THREE

r

THE CONSTITUTION OF A HA CKER

With every generation of humane there are certain types-
of individual* that emerge. There are (always have been and
always wilt be) leaders, followers, general nuisances, etc.
And then there are folks who like to play with things and
figure out how they work.

Before technology came along, there really wasn't all that
much for these people to play around with. And certainly
there was no way for them to pool their resources except
through face-to-face communications.

With telephones, of courts all aspects of human life
changed. Here was a toy that anyone could play with and get
virtually unlimited results. But of course, most people did n’t
(and don't) see it that way— rphones are phones and nothing
more. You're not supposed to have fun with them. Yet,
certain adventuresome type* insisted on having fun with
their phones anyway. Tjiey : did all kinds of things they
weren't supposed to dg T like figure out the way phones work
and interconnect. For the first time, these technological
enthusiasts posed a "threat** to technology by reaching out
and touching it rather than simply using it without asking
any questions.

Today there .are Jots of people still having fun with their
phones and mi king af I kinds of technological advancements
of their own. But the real focus at the moment is on the
newest "threat," people who like to experiment and have fun
with computers. Not the kind pf fun thcyYe supposed to be
having with Pacman^and Mr. Do*, but unauthdriietf fun
with other people's computers.

Why do they do this? What do these people possibly have
to gain by breaking into computer systems and seeing things
that don’t really concern them or I hat is of no possible use to
them? In the great majority of cases, computer hackers
don't gain anything niatefial or financial from their
exploration. Add lolhiit the high risk of getting caught and
it becomes very hint for the average citizen to understand
whpt motivates these people..

Many computer . hobbyists, in fact, are resentful of
hackers, consign (bent immature and troublesome.
Quite a fc w conDputfcr hu Ucttn boards prohibit certain topics
from being discussed, $i)df wtipn they do, hacking is almost
always one of them. Tigris, is some justificat ion behind this,
since the image of ailcomputcr users can be adversely
affected by what t|^ dp.

There are pisii the ..tagal people who insist on telling
everyone that jbtrica king into ^computer hy phone is just like
physically bneatih&iiiioa home or office. Fortunately, that
logic seems to feejsbpred by very, few people.

In spite of dH/oCf^ greats and ciiticism, though, the
hackers arc SOI thpif aci," And public opinion,

particularly apjo^g t be young, seems to be in their favor,
mostly as a rtsuti of media Coverage

There’s, even a ivebkty TV program about hackers called
Jhe \Vfu 2 /ffr^4J^eh%ek, this group of a mazing kids has a
new adventure. The scripts area bit moronic but interesting
nonetheless. In gne episode, the kids (only one of which is a
true hacker) find out about an evil person who happens to be
stealing Social Security checks. (They discover this by
casually logging into his bunk account.) To leach him a

lesson, they break into another computer and enter his name
as being deceased- In each program, these kids break into at
least one new computer. But do they ever get into trouble?
Of course not. First of all, they’re only children. And second,
they're entering these computers for good reasons, even if
they are unauthorized.

Now what kind of message is this program conveying?
Apparently, it's OK to invade other people’s privacy if your
intentions are ultimately "good." It sounds Like something
Reagan would gel a kick out of.

A genuine hacker breaks into computers for the
challenge. He's not out to save the world, nor to destroy it.
He is not out to make a profit out of what he's doing.
Therefore, it's not fair to categorize him as a criminal and it's
just as wrong to say he’s some sort of a savior.

Technological enthusiasts operate with the same
motivation that a good mountain climber has. Regardless of
what may happen to him, a computer hacker wiilaAvfiyj be
interested in playing with computers. It’s in his nature. And
any laws that are created to “eliminate” hacking simply
won't work because of these facts. There will always be
people who want to experiment with things and this urge
cannot be stifled. Did hacking come to a grinding hall
because of the “414" scandal? Or because of the Tclemail
raids? No. Judging From the proliferation or computer
bulletin boards where hacking is discussed, it's getting
bigger than ever.

The realistic way for the owners of large computer
systems to look at this is to regard backers as necessary
security checks. That's right. Necessary because if the
hackers weren't the ones to break in, who would be? Let’s
assume that hackers had never even tried to break into the
Memorial 51 can- Kettering Cancer Center computer.
Someone else would have, because the system was
practically wide open. And maybe they would have had a
reason to get into the system— to do various nasty things.
But now, because of what the hackers did, the Sloan-
Kettering system is more secure.

One could almost say that a person with hacking abilities
has an obligation to try and get Into as many different
systems as he can. Let's get nationalistic for a moment. If
you have the number for a top-secret government computer
in Ft, George G. Meade, MD, odds are that the Albanians
have it also. Now, would it be better for them to break into
the system and find out all kinds of nice things or for you to
break in and be discovered, forcing the system to become
more protected? And, if you do break in, don't you deserves
note of thanks for waking them up?

Keep in mind, though, that a computer hacker is undent
obligation to turn himselT in or warn operators that their
system is easily penetrable. It's the job of the sysops to notice
when their computers are being tampered with and if they
don't detect you, then that's a second security lapse for them.

This is a pragmatic view, however shocking it may seem.
In closing; wc should point out to the hackers themselves
that there is no need to worry or fret if their methods or
secrets are eventually d iscovered. This is only the beginning.
Our world is turning into a technological playground.

i

ALTER J> A I E LOING U1S1AJNLE

First of a persistent series — how the companies work and a guide to MCI

SWAGIMA. That’s the word that National Public Radio
uses to describe Long distance services. It stands for SBS (or
Skyline}, Western Union (or Metrofone), Allnet (or
Combined Network Services}, GTE Sprint, ITT, MCI, and
of course AT&T, And there are many more, each of which
will eventually be covered in our pages. Right now though,
we’d tike to give you an idea of what these systems arc and
how they work.

Except for AT&T, ail of the above systems work in a fairly
similar manner. (This will be changing very soon and very
dramatically under the terms of the Bell divestiture) Each
system has its own series of networks* i.e. land-lines, lines
leased from AT&T, microwave relays* satellite Links* etc.
They each have local city access numbers, although some
like Aiinet and MCI have special ways of using a "travel 1 *
service by dialing a special number* while Sprint uses a
"travelcode” to access nodes outside the subscriber’s city.
On others, like Metrofone, you can use the same
authorization code from any of their access points.

A long distance telephone company consists of four major
parts: you have your input — that is, a local access number or
a toll-free “£00” number to access the^ystem. When you do
this, a device called a “switch 41 answers, giving you the
familiar "computer dial tone” When you enter your
authorization code and destination number you are routed
over their network. The heart of the system is the controlling
system, which includes the "switch” This is the computer
that checks the authorization code, has provisions for time-
of-day restrictions, traveicodes, accounting codes, and the
like. They have a few provisions which the longdistance
services donY appear to use, such as the infamous “speed
number 11 recording which was a favorite of many phone
phrtaks (for reasons you’ll soon know if you don’t already).
The system checks to see if the Location being dialed is on the
network, and acts accordingly. It makes a Log of numbers
called, the authorization code, and time usage which is
stored on a word processing tape and then read by another
system for billing. Some companies charge in one minute
increments, although the system has the capability to record
time usage in 6 second increments.

There are quite a few different systems in use today. A
couple of the most common ones art made by Northern
Telecommunications, which is based in Dallas, Texas.
Another company that sells similar equipment is Rockwell
We scorn, MCI allegedly is in the process of buying new
switches from them, and they will be installed by Dynacomp
Telecommunications, also based in Dallas.

Microwave Links

Mast of the low cost services, at one point oranother* use

microwave antennas to transmit calls, Each microwave

. «■

station is Located about 30 miles from each other to make up
for the curvature of the earth since microwaves travel in a
straight line. Each of these stations has 4 dishes (at least).
One dish is used to receive from a previous station and one is
used to transmit to that station. The other two dishes do the
same thing to the destination station — one receives and one
transmits. So if you make a call 3000 miles away* you may
wind up going through 100 different microwave stations,
many of which you can see next to major highways.

This is how the alternate long distance companies manage
to charge less than AT&T; they use their own systems. But
this is also why, in many instances, (he sound quality is

poorer on the alternate services. Remember, a chain of
microwave towers is only as strong as its weakest
connection.

A Look at MCI

MCI (Microwave Communications Inc.) was the first new
kid on the block, way back in 1967 when the idea of an
alternate phone service was almost unheard of and
practically illegal. MCI was fust used solely by businesses
who wanted to communicate between the cities of Chicago
and Cleveland That was it. And even with this amazingly
limited system* MCi ran into problems with AT&T, who
didn't want anybody trying to do what they did. Lawsuits
followed, with MCI e ventually getting a prombe of eventual
equal access, to the AT&T network. In fact, MCI’s legal
action is considered one of the motivating factors behind the
break-up of the Bell monopoly.

Now MCI is the biggest of the alternate services (they
have well over a million subscriber* at present, having
opened their doors to residential customers a mere 5 years
ago) and also one of the hardest to penetrate. The system has
5 digit codes that art entered before the (0 digit phone
number, a total of 1 5 digits. But these codes only work from
one location, making it rather unlikely to find one by
guesswork. If you want to use the system from another city,
you have to sign up for MCI “credit card" service which
costs an additional S5 a month (on top of an initial IS a
month charge for the regular service). Here you get a List of
48 phone numbers around the country and a 7 digit code
which can be used from any one of them,, Most code seckcre
prefer scanning the “credit card” numbers since more
numbers work overall. However, a strong argument can
often be heard in favor of the 5 digit number* that are
located in densely populated areas. like Los Angeles or New
York. Naturally* the odds of finding something increase
under those circumstances.

No Proven Method For Finding Codes

MCI, being the oldest of the companies* has learned quite
a bit in (hat time. Therefore, no major bugs are still crawling
around on their system. Hacker* have many theories on
number patterns, of course. For example* numbers like
22212 or 12345 tend not to work. In other words, your guess
is as good as our*. As far as what they do when they know a
code is being abused, MCI seems to be more interested in
changing the code rather than laying a trap, as other
companies have been known to do< Of course, this doesn’t
mean that they're incapable of doing such a thing.

MCE Features

The MCI tone sounds like all the others (a hoUowish*
medium-pitched, steady tone), but it has its own set of
recordings, depending on what you do to it. If you enter an
invalid code*, you’ll hear a mechanical female say; "THEE
AUTHORIZATION CODE YOU HAVE DIALED IS
INVALID TWO ZERO THREE" and then an ESS reorder
that trips over itself (listen to it and you’ll understand}. If
you dial someplace you're not supposed to call (for whatever
reasons), you’ll hear “THEE NUMBER YOU HAVE

dialed isnot on the network TWO ZERO
THREE" and (he reorder. Each MCI dialup has its own 3
digit identity code and they tend to be simitar the doser
together they are.

Many businesses are installing MCI “dedicated lines" in

{continued on page 4)

c

I
¥

718 is coming!

I lM PiIlY,- Yfli* ItlTWI

The New York Stale Public Service Commission has
voted to begin dividing New Yprk City into two area codes
on September I to "prevent an impending exhaustion of
telephone numbers/' At that timc + the old 2 1 2 area code wilt
begin to reach only Manhattan and the Bronx, whereas a
brand new area code, 718, wilJ start to work for Brooklyn,
Queens, and Staten Island. The whole system becomes
mandatory on January 1* 1985,

Charles Herndon, a New York Telephone spokesman,
said that the 718 code was assigned to the city years ago by
the North American Dialing Plan, a group that administers
area codes in the U.S.* Mexico, and Canada.

"Of the numbers available at the time, 718 was the best*"
he said, "There weren't that many available ”

The P,S.C. rejected recommendations by a consultant
{Economics and Technology* Inc.) hired by the City Board
of Estimates. Those recommendations called for the
implementation of the 718 area code, however, instead of
using it for people* the consultant suggested using it
exclusively for computers, paging systems, and other
devices, since they were the main reason for the new area
code in the first place.

[2600 would like to go on record as enthusiastically
supporting the idea of an entire area code of machine;.]

Supercomputer dialups

l |, Ji)sin TwJay

Astronomy and astrophysics are gathering so much data
by telescope these days* that it cannot be handled by
conventional computers* according to Dr Vincent Icke of
the University of Minnesota.

To remedy the problem, Dr. take called for the creation of
a central supercomputer facility that would be at the
disposal of all astronomers and astrophysicists nationwide
via telephone lines.

Wiretap City

I he p r >v Vflrt. furo

After an investigation, the New Haven (Connecticut)
Board of Police Commissioners* a civilian body that
oversees the Police Department, revealed in 1978 that the
department had routinely tapped the phones of residents
from 1964 to 1971, apparently to monitor radical political
activity. This* the board said* was illegal.

In December 1982, after it had been disclosed that the
phones of some JOOO residents had been tapped, the Federal
District Court in Bridgeport made the case a class action*
inviting anyone who felt wronged to become a plaintiff.

So Far, 1230 people have become plaintiffs, They include
several judges, lawyers, and other prominent political
figures and* of course, a great many members of the Yale
faculty.

Students Cause Havoc in Computer

< firsts Shuikui

A group of students at Gompers Secondary School in San
Diego tapped into the school's computer system last month,
causing uJ| kinds of problems.

"It was funny at first when t he kids changed the passwords
so the teachers couldn't g ct ' nt0 their programs in the
system," said Alex Rascon, a school official, "But then they
started deleting grades, altering ihe other kids" homework,
and tampering with the teachers' Hies.

"These kids art whizzes— ihey're very bright," he went on,
"Fortunately we caught it before too much damage was
done. At this point it can be easily corrected "

Albert Cook, the assistant San Diego superintendent,
took the sorehead approach. “We still haven't decided
whether charges will be filed with the San Diego Police
Department," he said.

The Person Numbers

Tk AmtcLiKd I'm*

Sweden's Person Number is a 10-digit figure that tells who
you arc, where and when you were born, and your sex. Every
computer file in the country is based on the Person Number,
whether it's at a bank, a hospital, an employer, the social
welfare office, or the tax authorities.

Person Numbers went into effect on January 1 , 1947 and
were computerized 20 years later. Recently, a government
study suggested the creation of a super-databank (based on
the Person Number) that the Central Bureau of Statistics
could use freely. By calling up a Person Number on a
terminal, the bureau would be able to find out details on
everything from a person's illnesses and criminal record to

his income and debts.

Critics of the plan see this as an erosion of civil liberties.
One said, "The files will collect more information on a
person than he can remember himself."

Furthermore...

iMhf Newt

* All computers seized by the FBI last October during the
Telemail raids haveeilher been returned already orare in the
process of bemgsent back. New developments in Lhecasc are
expected shortly,

* Telenet now hangs up after 3 connection attempts,
whether they're successful or not. This means that last
month's article {Hacking on Telenet) is already slightly
outdated* but only until somebody figures out a way around
this latest hurdle.

■ Some more signs of the divestiture— this time it's the
: 956 exchange. This is a universal exchange that is {or will
soon be) working everywhere. 950-1022 and 950-1088 give
alternate long distance dia llones. (The latter belongs to
Skyline.) The connection is crystal clear and toll-free,
Eventually* the 950 will be dropped and you will dial 1 OX X
to make long distance calls* where XX is the carrier of your
choice. You can't access 95G's in other area codes,

* Eastern Airlines has changed its mind about allowing
, portable computers on Bights, leaving only American

Airlines maintaining the ban.

* 202 and 214 now have automated directory assistance
too. Have you cheeked your area code today/

THE FIRST A TOMIC BOMB

A TRUE TALC

This story was originally related by Laura Fermi, widow
of the nuclear physicist Enrico Fermi, who, along with
assorted co i leagues, participated in the first test bomb in the
desert outside Alamogordo, New Mexico in the early
morning hours of a summer day in July. 1945

When the dale had been established for the secret lest,
staff members from the Manhattan Project (as the secret test
was known } were invited to bring their spouses to New
Mexico to watch the results of the several years of research.
Each staff member had been assigned specific tasks to
handle while there. Generally, they acted as observers and
were stationed in a circle around the perimeter of the bomb
site. Enrico and Laura were stationed in an area about
twenty miles to the southwest of the bomb site.

the morning came when the bomb was scheduled to be
detonated in the test. Laura told if like this...

Enrico and I woke up at 3:00am, to go to the site. The test
was scheduled for 4:30am that day, which was July 19, 1945,
We drove to our post, about twenty miles from the site. It
had been arranged that the nearly one hundred of us present
would be Located in a circle a bout 100 milts in circumference
surrounding the bomb site. We were all to be tn
communication with each other over, telephones, all of
which were connected through the exchange in
Alamogordo.

We arrived at the site at 4: 15 am and almost immediately
it began to rain, quite a heavy, very typical torrential
downpour during the summer. We waited in our car, and at
4:30 am the time came and went, but the bomb did not go
off. Enrico and 1 assumed it might have been postponed due
to the rainstorm, but decided to check with the other staff
members to see for sure. For some reason, the telephone
there at the site did not seem to work; the operator would
not respond, (Note: At that time, nearly all phones in the
United Slates, and certainly in New Mexico, were manual.
No dialing of any sort war possible — you had to use the
operator for everything .)

Finally Enrico decided that we would drive into town and
try to contact the others and see what went wrong. So we
drove back to town, and got there about 5:15 am. The only
place open at that time of night was a hotel, and we stopped
in thereto use a pay phone. Strangely enough, the pay phone
was not working either, or at least the operator never came
on the line to ask what we wanted. Enrico was quite curious
about all this and decided to investigate. We went outside
the hotel, and Enrico found where the telephone wires came
off the pole and down into the building. He decided that we

would follow the wires, so we walked down the street
looking overhead at the wires on the pole as we went along.
Finally, we turned down one street and saw a house. The
telephone poles and wires from all directions seemed to
come down to this house. There must have been hundreds of
wires from telephone poles all coming down onto the side of
this house and going in through an opening

Wc noticed that there was a front porch light which was
on. The front door was open, but there was a screen door
which was closed. We went up on the front porch and looked
into the house, A switchboard was there, and there were a
dozen or more lights on the switchboard Ik, blinking off and
on as pcdple were flashing the switch hooks on their phones
trying to raise the operator. The room was just dimly lit, and
near the switchboard was a sofa, and a woman was laying on
the sofa sound asleep] Enrico pounded very loudly on the
screen door, and shouted at the woman. Suddenly she
opened her eyes and looked at him, very startled. Then she
looked at the switchboard. Immediately she sprang up,
dashed over to the board, sat down and began frantically
answering the calls.,;

Without saying any more, Enrico and 1 left, went back to
the hotel where our car was parked, and drove back to our
monitoring post twenty miles out into the desert. We had
been at our post only about five minutes when the explosion
went off, at about 6:50 am, which was two hours behind
schedule. Later, we talked to the other staff members and
found that there had been some confusion because of the
raim None of them had been able to reach the others because
the telephone operator had fallen asleep, and the phones
were not getting answered /connected...

We on the staff all had a big Laugh out of it, but nothing
more was ever said or done, and [ doubt to this day that
that woman is even aware that the first atomic explosion in
the world was delayed two hours because of her.

Amazing, but true. Alamogordo was a tiny town back in
the 4Q r s, and it's very doubtful that the night operator had
ever seen so much traffic in her life as the hundred or so
people all on the line at once that early morning. More than
likely, the poor dear had had a very rough day the day
before, in the miserable summer heat, had been unable to
sleep during the day, and had come to work that night
thoroughly exhausted. She probably decided that "it won't
hurt just to dose mv eyes for a minute ... " and the rest of the
story is already told. After alt, experience had taught her
that in fact she would not usually get a dozen calls all night
on her shift, and she felt relatively safe in stretching out "just
for a minute”.

Do you have a story about computers or phones? Send it to us! If we print it, you’ll get a
year’s subscription to 2600! The address ; 2600, Box 752, Middle Island, NY 1 1953.

(continued from page 2)

their offices, which takes away the task of having to dial the
MCI access number. In addition, you don't, have to enter an
authorization code and you don't even have to have touch-
tones 6 . You simply pick up the phoneand there's your MCE
dialtone! According to MCE, you have to make at least S75
worth of out-of-state calls per month for this system to pay
off. Of course, you cant access operators 1 , directory
assistance, 800 numbers, and that sort of thing because
I) MCE doesn't support any of those services and 2) they're
certainly not going to let you connect to something (hey
can't charge you for. OF course, if you know what you're

doing, you can route calls in such A way that numbers that
aren't supposed to go through for you will work, and Cod
knows where it finally shows up! This doesn't involve extra
codes, blasting the line with tones, or anything overly
suspicious. AIL you need is the right combination of area
codes. Now this has been proven to work with MCI
dedicated lines; it's rumoured to work on dial-ups as well,.,
Finally, MCI is starting to offer its own phone booths at
airports, which we'll report on as soon as wc find one. And
of course, there's MCI Mail, an electronic overnight mail
service started up last fall which hackers are currently
probing. When we get conclusive results on that, we'll pass
them along. MCI can be reached at 8006246240.

2600

page

The following is a list of hosts that are accessible throu
ARPANet* ARPANet connects many systems together, allowing them to sc
electronic mall, transfer files, and be able to work on each other
computers. The network is very intricate, containing many subnet
including the one below, called "MILNET" #■ short for "Military Network
That is, our military. This is a small list, encompassing approximate
one twentieth the entire number of systems accessible through ARPANe
Notice the PENTAGON-TAC below. This Is an access point for people in t
government.

address:

Host name :

Host type:

Operating

H H H H H _ a |

i± *■-" * s s s

e ^ t; z z ~ ~ ~ ~ ~

26.0.0.3

NOSC-CC

VAX-11/750

□NIX

26 . 2 * 0 * 3

L0GIC0N

PDP-11/70

UNIX

26-3,0.3

NPRDC

VAX-11 / 780

UNIX

26.0.0.8

NRL

VAX-11/750

□NIX

26.1.0.8

NRL-AIC

VAX- 11/780

UNIX

26.2.0.8

NSWC-W0

VAX- 11/ 750

UNIX

26.3.0.8

NRL-T0PS10

DEC-10

TOPS 10

26.6.0,8

NRL-ARCTAN

PDP-11/40

RSX11

26.7.0.8

NRL-CSS

VAX-11/780

UNIX

26.1.0.13

GUNTER-ADAM

DEC- 2 060

TOPS 20

26.3.0.13

J ATC-KEES1

BURROUGHS- B/ 29

BT0X/UNIX

26, 0.0+14

CMU-CS-B

DEC T 1050

T0PS10

26.6.0.16

RIACS- ICARUS

VAX-11/730

UNIX

26.0.0.17

MITRE

C/70

UNIX

26.0.0.18

RADC-MULTICS

H0NEYWELL-DPS-B/70M

MULTICS

26.3.0.18

RADC-TOPS20

DEC- 204 0T

TOPS 20

26.5.0.18

RADC-UNIX

PDP-11/45

UNIX

26.G.0.1B

GE-CRD

VAX-11 /780

VMS

26.0.0+19

NBS-VMS

VAX- 11/ 780

VMS

26.1.0.19

NBS-SDC

VAX-11/7B0

VMS

26.2.0+19 -

NBS-UNIX

VAX- 11/ 750

UNIX

26.3.0.19

NBS-PL

PDP-11/70

UNIX

26+6.0.19

NBS-AMRF

VAX-ll/780

VMS

26.7.0.19

NBS-SSI

VAX-11/750

UNIX

26.4.0.20

DCA-EMS

C/70

UNIX

26.0.0.23

USC-ECLB

DEC-1090B

T0PS20

26.3+0.2 3

USC-ECL

DEC- 109 0B

TOPS20

26.0.0.24

NADC

VAX-ll/780

UNIX

26.1.0.25

DDN1

C/70

UNIX

26 .0.0. 26

PENTAGON-TAC

C/30

TAG

26.3.0.26

TCACCIS-CSC

VAX-ll/750

VMS

26.0,0.29

BRL

PDP-11/70

UNIX

26.1.0.29

APG-l

C/70

UNIX

26.3.0.30

ATC -HANOI

BURROUGHS -8/ 29

btos/unix

26+0.0+33

NPS

PLURIBUS

PLI

26+3.0,33

FNOC-SECURE

PLURIBUS

PLI

26.0.0.35

N0SC-SECURE2

PLURIBUS

PLI

26.1.0.35

NOSC-TECR

VAX-ll/780

VMS / EUNICE

26.3.0.35

N0SC-SECURE3

PLURIBUS

PLI

26.4.0.35

N0SC-F4

F00NLY-F4

FO0NEX

26+0+0+36

COINS-TAS

PLURIBUS

PLI

26+1.0.36

HAWAII-EMH

C/ 70

UNIX

26+0.0.39

EDWARDS-VAX

VAX-11/7B2

VMS

26.1+0+39

EDWARDS-2060

DEC-2060T

TQPS20

26. 1.0.45

ARDC

VAX-ll/780

UNIX

26.3+0.46

0KC-UNIX

PDP-11/70

UNIX

26.1+0+48

AFWL

PDP-11/50

RSXllM

26.0.0+49

BBNB

DEC- 10

TENEX

26.0,0.50

, DARCQM-TEST

VAX- 11/750

UNIX

26.3.0*50

LS5A-DB1

NAS3-5

MVS

26.7*0.50

ctl-ai

VAX-11/780

VMS

26.0,0.53

AFSOAD

PDP- 11/45

RSX11M

26,2.0.53

AFSODEV

PDP-11 /44

RSX11M

26,4.0*53

NCSC

VAX-11/750

UNIX

26.5.0.53

martin

PDP-11/45

RSX

26.6.0.53

EGLIN-VAX

VAX-11/ 780

VMS

26.2.0.54

ACC

PDP-11/ 70

UNIX

26*1.0.55

ANL-MCS

VAX-11/ 780

UNIX

26.2.0.55

COMP ION -VMS

VAX-11/750

VMS

26.0.0.57

TYCHO

PDP-11/ 70

UNIX

26 . 2 . 0 * S7

MARYLAND

VAX-11 / 780

UNIX

26. 0.0. SS

NYU

VAX- 11 / 700

UNIX

26.1.0.58

BNL

PDP-11/44

UNIX

26.3.0*60

CEC0M-1

F0ONLY-F4

TENEX

26.0.0.61

STL-H05T1

DEC-2040

TOF520

26.1.0.61

ALMS A- 1

VAX-11/ 750

UNIX

26.1.0.64

MARTIN -B

VAX-11/750

VMS

26,3.0.64

ROBINS-UNIX

PDP-11/45

UNIX

26.0.0.65

AF5C-5D

DEC-2020T

TOPS20

26.2.0.65

AEROSPACE

VAX-11/780

UNIX

26* 3.0*65

' MARTIN -ED

PDP-11/45

RSXUM

26.1*0*66

AFGL

PDP-11/50

RSX11M

26*3*0*66

MITRE- BEDFORD

VAX-11/ 780

UNIX

26.0,0*67

AFSC-HQ

DEC-2040T

TOPS20

26.1-0.73

SRI-HARF

PLURIBUS

PLI

26.4.0.73

SRI-F4

F00NLY-F4

TENEX

26.0.0.74

SIMTEL20

DEC-20 4 0T

TOPS 20

26.1.0.74

HSMR70A

C/70

UNIX

26.3.0.74

WSMR70B

C/70

UNIX

26.3.0.78

MCCLELLAN

PDP-11/ 70

UNIX

26.0*0.81

NEMS

VAX-11/750

UNIX

26.1.0.81

NALCON

VAX-11/750

UNIX

26*3.0*81

DTRC

VAX-11/780

UNIX

26. 0. 0.82

BBNCCT

C/70

UNIX

26.3.0*82

DDN2

C/70

UNIX

26.4.0. 82

BBN-RSM

PLURIBUS

PLI

26.9*0*82

TEPI

C/30

26.0.0.87

SANDIA

DEC-2O60T

TOPS 20

26 .0*0* SS

NLM-MCS

VAX-11/780

UNIX

26.0.0.90

LANL

VAX-11/750

UNIX

26.4,0+92

NAVDAF- NEWPORT

UNI VAC- 1100

CMS

26.1,0+95

Sl-A

FODNLY-F2

WAITS

26*2,0,95

Sl-B

VAX-11/750

UNIX

26.3.0.95

Sl-C

VAX-11/750

UNIX

26.2.0.97

FAXRV-NES

VAX-11/730

VMS

26,1.0.103

USC-ISIE

DEC-1090T

T0PS20

26.2*0.103

ADA- VAX

VAX-1 1/ 780

VMS

26.3.0.103

use- IS I

DEC- 1090T

TOPS20

26.1.0.104

DC EC-LSUS2

IBM-15&

MVS/SP

26,4.0.104

DCEC-LSUS

IBM-158

MVS /SF

26.3.0.106

ARPA-PNG11

PDP-11/34

EPOS

26.0.0.112

STL-HOST2

BBN-C/60

UNIX

26.0*0.117

KOREA- EMH

C/70

UNIX

6